To solve the problem that decrease in [BH] max of a magnet and increase in magnet wall thickness which are caused due to increase in the used amount of epoxy resin are necessary in the conventional core built-in type magnet, and proper quality of magnet power cannot be reflected in motor characteristic.

Magnet powder green compact, iron powder green compact and a rotating shaft are heated, and collectively turned into a rigid body at the same time, thereby forming the core built-in type magnet rotor.